Search results for "Perfusion scanning"
showing 10 items of 32 documents
Abnormal Myocardial Perfusion After Infarction in Patients With Persistent TIMI Grade-3 Flow. Only an Acute Phenomenon?
2007
Introduction and objectives It has been suggested that abnormal perfusion as derived from cardiovascular magnetic resonance imaging (CMR) is a transient dysfunction of microcirculation after myocardial infarction (MI) with TIMI 3 flow. We hypothesized that defects of myocardial perfusion may persist during the following months. Methods Forty-seven patients with MI and sustained TIMI 3 flow underwent intracoronary myocardial contrast echocardiography (MCE) 1 week and 6 months after infarction. Abnormal perfusion by MCE was regarded as >1 hypoperfused segment. Results At one week, 20 patients showed abnormal perfusion as derived from MCE. At six months 10 patients displayed chronic abnormal p…
Impaired Cerebrovascular Autoregulation in Large Vessel Occlusive Stroke after Successful Mechanical Thrombectomy: A Prospective Cohort Study
2020
Abstract Introduction: Successful thrombectomy improves morbidity and mortality after stroke. The present prospective, observational cohort study investigated a potential correlation between the successful restoration of tissue perfusion by mechanical thrombectomy and intact cerebrovascular autoregulation (CA). Objective: Status of CA in patients with large vessel occlusive stroke after thrombectomy. Methods: After thrombectomy CA was measured using transcranial Doppler ultrasound. For this purpose a moving correlation index (Mxa) based on spontaneous arterial blood pressure fluctuations and corresponding cerebral blood flow velocity changes was calculated. CA impairment was defined by Mxa …
Blood-brain barrier disruption by low-frequency ultrasound.
2006
Background and Purpose— A recent study showed a dramatic increase in cerebral hemorrhage comprising atypical locations with low-frequency ultrasound–mediated recombinant tissue plasminogen activator–thrombolysis in humans. Here, we provide a possible explanation for this phenomenon by a side effect observed in a study using the similar ultrasound device. Methods— The study was originally undertaken to investigate by transcranial Doppler sonography, positron emission tomography and perfusion MRI whether transcranial application of wide-field low-frequency ultrasound (300 kHz) improves cerebral hemodynamics in patients with cerebral small vessel disease. Results— Showing no clear positive ef…
MRI of tarantulas: morphological and perfusion imaging.
2005
This paper describes a study performed to evaluate the feasibility of using a 1.5-T whole-body magnetic resonance imaging (MRI) equipment, in combination with pharmacokinetic modeling, to obtain in vivo information about the morphology and perfusion of tarantulas (Eurypelma californicum). MRI was performed on three tarantulas using spin-echo sequences for morphological imaging and a rapid spoiled gradient-echo sequence for dynamic imaging during and after contrast medium (CM; Gd-DTPA) injection. Signal enhancement in dynamic measurements was evaluated with a pharmacokinetic two-compartment model. Spin-echo images showed morphological structures well. Dynamic images were of sufficient qualit…
Myocardial blood flow quantification for evaluation of coronary artery disease by computed tomography
2017
During the last decade coronary computed tomography angiography (CTA) has become the preeminent non-invasive imaging modality to detect coronary artery disease (CAD) with high accuracy. However, CTA has a limited value in assessing the hemodynamic significance of a given stenosis due to a modest specificity and positive predictive value. In recent years, different CT techniques for detecting myocardial ischemia have emerged, such as CT-derived fractional flow reserve (FFR-CT), transluminal attenuation gradient (TAG), and myocardial CT perfusion (CTP) imaging. Myocardial CTP imaging can be performed with a single static scan during first pass of the contrast agent, with monoenergetic or dual…
Long-term prognostic implications of revascularization in patients with known or suspected chronic coronary syndromes without ischemia in vasodilator…
2021
In this study, we evaluated the association between symptoms-guided revascularization occurred within three months following a negative vasodilator stress cardiovascular magnetic resonance (negative stress-CMR) and long-term adverse events in patients with known or suspected chronic coronary syndrome (CCS).We retrospectively evaluated 3517 patients in which the stress first-pass perfusion imaging revealed no ischemia. The primary endpoint was the composite of death, spontaneous myocardial infarction, heart failure (HF), or stroke. The association between symptoms-guided revascularization after a negative stress-CMR and the endpoint was assessed using the multivariable Cox proportional hazar…
Prognostic value of cardiac CT
2020
In the past decades, coronary computed tomography angiography (CCTA) has become a powerful tool in the management of coronary artery disease. The diagnostic and prognostic value of CCTA has been extensively demonstrated in both large observational studies and clinical trials among stable chest pain patients. The quantification of coronary artery calcium score (CACS) is a well-established predictor of cardiovascular morbidity and mortality in asymptomatic subjects. Besides CACS, the main strength of CCTA is the accurate assessment of the individual total atherosclerotic plaque burden, which holds important prognostic information. In addition, CCTA, by providing detailed information on corona…
Quantitative magnetic resonance imaging for focal liver lesions: bridging the gap between research and clinical practice
2021
Magnetic resonance imaging (MRI) is highly important for the detection, characterization, and follow-up of focal liver lesions. Several quantitative MRI-based methods have been proposed in addition to qualitative imaging interpretation to improve the diagnostic work-up and prognostics in patients with focal liver lesions. This includes DWI with apparent diffusion coefficient measurements, intravoxel incoherent motion, perfusion imaging, MR elastography, and radiomics. Multiple research studies have reported promising results with quantitative MRI methods in various clinical settings. Nevertheless, applications in everyday clinical practice are limited. This review describes the basic princ…
Vasodilator Stress CMR and All-Cause Mortality in Stable Ischemic Heart Disease
2020
Abstract Objectives This study explored the association of ischemic burden, as measured by vasodilator stress cardiovascular magnetic resonance (CMR), with all-cause mortality and the effect of revascularization on all-cause mortality in patients with stable ischemic heart disease (SIHD). Background In patients with SIHD, the association of ischemic burden, derived from vasodilator stress CMR, with all-cause mortality and its role for decision-making is unclear. Methods The registry consisted of 6,389 consecutive patients (mean age: 65 ± 12 years; 38% women) who underwent vasodilator stress CMR for known or suspected SIHD. The ischemic burden (at stress first-pass perfusion imaging) was com…
Study of Post-Infarction Coronary Perfusion Using Quantitative Analysis of Myocardial Echocardiography With Intravenous Injection of Contrast
2005
Introduction and objectives. After a myocardial infarction, damage to the microcirculation indicates a worse prognosis. We compared the usefulness of the quantitative analysis of myocardial contrast echocardiography with intravenous injection of contrast (MCE-iv) with intracoronary injection (MCE-ic) for analyzing coronary perfusion. Patients and method. We studied 42 patients with a first ST-elevation myocardial infarction, single-vessel disease and a patent artery (TIMI 3, stenosis 0.75) and MCE-iv (perfusion of SonoVue, singleimage capture in 1 out of each 6 cycles with trigger set at end-systole, perfusion considered normal if >0.9). Perfusion was considered abnormal if 2 or more segmen…